Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 


Oil and water: an icy interaction when oil chains are short, but steamy when chains are long

Water transforms into a previously unknown structure in between a liquid and a vapor when in contact with alcohol molecules containing long oily chains, according to Purdue University researchers. However, around short oily chains water is more icelike.
Water plays a huge role in biological processes, from protein folding to membrane formation, and it could be that this transformation is useful in a way not yet understood, said Dor Ben-Amotz, the professor of chemistry who led the research.

Ben-Amotz's research team found that as they examined alcohols with increasingly long carbon chains, the transformation occurred at lower and lower temperatures.
When in contact with a chain seven carbon atoms long, the water molecules became much looser and more vaporlike at a temperature of 140 degrees Fahrenheit, which is about halfway between the melting and boiling points.

"For oils with chains longer than four carbons, or about one nanometer in length, we saw the water transform into a completely new structure as the temperature rose," Ben-Amotz said. "If the trend we saw holds true, then this transformation could be happening at body temperature around important physiological molecules like proteins and phospholipids."

Water responds very sensitively in its structure to small changes, he said.

"Water's versatility is what makes it so special," he said. "For instance, the surfaces of proteins have both oily and charged regions; and water changes itself to accommodate these very different components and everything in between. We are learning more about exactly how it does this."

The researchers found that water molecules interacting with the oil always formed a more ordered, icelike structure at lower temperatures, while the bulk of the water remained liquid. This ice-like structure would melt away as the temperatures increased and in longer molecules a new structure would appear, he said.
A paper detailing the National Science Foundation-funded work is published in the current issue of Nature and is also highlighted in a news and views article in the same issue. In addition to Ben-Amotz, co-authors include Purdue graduate student Joel Davis and postdoctoral fellows Kamil Gierszal and Ping Wang.

The team's observations add to a more than 70-year debate over the interaction of oil and water, with some studies suggesting that water forms little icebergs around the oil molecules, while others point to a more disordered, vaporlike water structure.
"This question was really up for grabs until we introduced an experimental method that could see these subtle changes in water structure," Ben-Amotz said. "Surprisingly, we found that both sides are right, and it depends on the size of the oil."

The challenge of the experiment was that the team needed to see the very small number of water molecules that are in contact with the oil chains in the presence of a very large number of other water molecules.
The team combined Raman scattering and multivariate curve resolution to create an analysis method capable of managing an unprecedented signal-to-noise ratio of 10,000-to-1.

"Most people never take a spectrum with a signal-to-noise ratio greater than 100-to-1, but if we performed this experiment that way we wouldn't see anything," Ben-Amotz said. "We needed to have a higher signal-to-noise ratio because we were looking for a needle in a mountain-sized haystack."

Raman scattering involves shooting a beam of light containing photons into a sample. As the photons hit molecules within the sample, they lose or gain energy. Such measurements create a spectrum of peaks that reveal the vibrational motions of the molecules present in the sample. Shifts in the peaks' shapes can show changes in the strength of bonds between water molecules and whether the molecules are becoming more or less ordered.

"With Raman scattering the bulk of the water creates a mountainous peak in the spectrum that buries everything else," Ben-Amotz said. "Multivariate curve resolution lets us see small changes in water structure under that mountain. As is often the case in science, the key was combining two already established techniques in a new way."

Davis said the team next plans to explore the effects of changes in pH and ionic charges on this transformation with the goal of making the experiments more relevant to proteins and biological systems.

"We are trying to better understand the driving forces of the behavior of proteins and cell membranes that are critical to our health," he said. "The role of water is an important piece of the puzzle."

Writer: Elizabeth K. Gardner, 765-494-2081,

Sources: Dor Ben-Amotz, 765-494-5256,

Joel Davis,

Elizabeth K. Gardner | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht High-arctic butterflies shrink with rising temperatures
07.10.2015 | Aarhus University

nachricht Long-term contraception in a single shot
07.10.2015 | California Institute of Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Weltrekord am TRIGA Mainz: 20.000 Pulse in 50 Jahren

Forschungsreaktor hat Anfang Oktober einen neuen Meilenstein erreicht

Der Forschungsreaktor TRIGA an der Johannes Gutenberg-Universität Mainz (JGU) hat zwei Monate nach den Feierlichkeiten zu seinem 50-jährigen Bestehen einen...

Im Focus: Startschuss für eine neue Ära der Präzisionsastronomie

Für die MICADO-Kamera, das Instrument mit dem das European Extremely Large Telescope (E-ELT) seine ersten Bilder machen wird, beginnt eine neue Phase: In einer gemeinsamen Absichtserklärung (Memorandum of Understanding) auf der „Kick-off“-Konferenz in Wien bestätigten die Partner in Deutschland, Frankreich, den Niederlanden, Österreich und Italien ihre Teilnahme am Projekt. Zwei Wochen zuvor, am 18. September, hatten das Konsortium und die Europäische Südsternwarte (ESO), die das Teleskop baut, den entsprechenden Kooperationsvertrag unterzeichnet. Nach diesen Meilensteinen tritt das Projekt nun in die Designphase ein.

Als erste, dedizierte Kamera für das E-ELT wird MICADO beugungsbegrenzte Abbildungen bei Nah-Infrarot-Wellenlängen (Wärmestrahlung) mit dem Riesenteleskop...

Im Focus: Kick-off for a new era of precision astronomy

The MICADO camera, a first light instrument for the European Extremely Large Telescope (E-ELT), has entered a new phase in the project: by agreeing to a Memorandum of Understanding, the partners in Germany, France, the Netherlands, Austria, and Italy, have all confirmed their participation. Following this milestone, the project's transition into its preliminary design phase was approved at a kick-off meeting held in Vienna. Two weeks earlier, on September 18, the consortium and the European Southern Observatory (ESO), which is building the telescope, have signed the corresponding collaboration agreement.

As the first dedicated camera for the E-ELT, MICADO will equip the giant telescope with a capability for diffraction-limited imaging at near-infrared...

Im Focus: Locusts at the wheel: University of Graz investigates collision detector inspired by insect eyes

Self-driving cars will be on our streets in the foreseeable future. In Graz, research is currently dedicated to an innovative driver assistance system that takes over control if there is a danger of collision. It was nature that inspired Dr Manfred Hartbauer from the Institute of Zoology at the University of Graz: in dangerous traffic situations, migratory locusts react around ten times faster than humans. Working together with an interdisciplinary team, Hartbauer is investigating an affordable collision detector that is equipped with artificial locust eyes and can recognise potential crashes in time, during both day and night.

Inspired by insects

Im Focus: Heuschrecken am Steuer: Uni Graz erforscht Kollisionsdetektor nach Vorbild von Insektenaugen

Selbstfahrende Autos könnten in absehbarer Zukunft auf unseren Straßen unterwegs sein. Ein innovativer Fahrzeugassistent, der bei Kollisionsgefahr das Steuer übernimmt, wird gerade in Graz erforscht. Manfred Hartbauer vom Institut für Zoologie der Karl-Franzens-Universität hat sich die Basis dafür in der Natur abgeschaut: Wanderheuschrecken können in brenzligen Verkehrssituationen etwa zehnmal schneller reagieren als Menschen. In Zusammenarbeit mit einem interdisziplinären Team erforscht er einen kostengünstigen Kollisionsdetektor, der mit künstlichen Heuschrecken-Augen ausgestattet ist und drohende Zusammenstöße bei Tag und Nacht rechtzeitig erkennen kann.

Tierisches Vorbild

Alle Focus-News des Innovations-reports >>>



im innovations-report
in Kooperation mit academics

Wasserstoff-Speicher als Wegbereiter für die Energiewende

08.10.2015 | Veranstaltungen

Herbstzeit ist Weiterbildungszeit - Von Stressbiologie bis Täter-Opfer Ausgleich

08.10.2015 | Veranstaltungen

Energieforum 2015: Was können Wasserstofftechnologien leisten?

08.10.2015 | Veranstaltungen

Weitere VideoLinks >>>
Aktuelle Beiträge

Eye-Tracking: Erstmals Blickmuster von Wellenreitern in standardisierter Umgebung erfasst

08.10.2015 | Kommunikation Medien

Photonen als Treibstoff für elektrischen Strom

08.10.2015 | Energie und Elektrotechnik

Weltrekord am TRIGA Mainz: 20.000 Pulse in 50 Jahren

08.10.2015 | Physik Astronomie